JP7277097B2 - Automotive engine cooling system leak-stopping formulation - Google Patents

Description

The present invention relates to an automotive engine cooling system leak stop formulation for repairing leaks in engine cooling systems, compatible with conventional coolant antifreeze types, drained and refilled with coolant. Repairs can be maintained at a later time.

Cooling systems, such as those in automobiles, can develop small leaks that can be difficult to locate or repair, e.g., these can be reached without significant disassembly of the engine system. be. Large leaks may require hose or gasket replacement, while small leaks can sometimes be repaired with a formulation added to the coolant.

Existing products for repairing small leaks fall into two distinct categories. One is based on sodium silicate chemistries, which are considered permanent repairs, but are not compatible with monoethylene glycol based coolant antifreeze. This is because such compositions form crosslinked gels in many monoethylene glycol-based cryoprotectant systems, which can lead to blockage of the cooling system. Another category is the so-called pour and go sealants based on a range of chemicals, which mix with monoethylene glycol based coolant antifreeze without clogging in the system. Falling into the latter of the two categories, these leak tight formulations can be used without first draining and flushing the engine coolant, which saves time, money, and trains the user in the art of auto repair. It has another advantage that it is not necessary. However, the repairs created by these products are usually not permanent and changing the coolant usually redissolves or washes away the seal. Likewise, these products are usually only suitable for repairing particularly small cracks or pinhole leaks in cooling systems.

Injection-acting sealants are added to the coolant to act to close leaks, but must not block the narrow flow passages that exist within the cooling system. The American Society of Testing Materials provides a standard method for testing the effectiveness of leak-stopping additives for engine coolants (ASTM-D3147-06). Most existing formulations sold in the EMEA region (Europe, Middle East, and Africa) fail to meet the requirements of the ASTM-D3147-06 standard and this test evaluates these products. provide an industry standard that can

Thus, a novel formulation capable of repairing leaks in engine cooling systems that meets the needs of vehicle owners, vehicle manufacturers and repairers and meets existing standards, particularly ASTM-D3147-06. There is a need for things. Specifically, it is compatible with engine coolant antifreeze, especially monoethylene glycol, and is a permanent repair, preferably a permanent repair even for very large openings in the minor-league category. A need exists for an injectable formulation that can form a

A need exists for formulations that can repair leaks in such a way that they can be considered permanent repairs. For the purposes of this specification, permanent is defined by three coolant changes. Current engine coolants vary in their protective capacity, but typically provide up to 5 years or 240,000 kilometers of protection for the cooling system. The average age of a vehicle varies by country, but is everywhere less than 10 years in developed countries across Europe, the Middle East, Africa, Asia, and North America. Three coolant changes are equivalent to 15 years or 720,000 kilometers, thus representing the useful life of most automobiles.

US Pat. No. 4,524,158 discloses a leaktight composition comprising a suspension of open fibers in an alcohol-based antifreeze composition. In British Patent Specification GB-1218485, (A) a liquid substantially inert to the interior of the container and to component B under the conditions in which the composition is used, and (B) dispersed in component A, comprising substantially spherical particles of a polymeric material insoluble in A, wherein the polymeric material of component B comprises one portion soluble in liquid A and a portion insoluble in liquid A but then In heat exchangers or other vessels designed to hold liquids containing polymeric dispersion stabilizers composed of complex polymeric molecules with other moieties soluble in the monomers forming the polymeric material. Disclosed is a liquid composition suitable for use as a leak stop agent in US-2003/0056691 discloses a liquid aluminum leaktight formulation for aluminum radiators. This formulation contains cellulose and polyester with aluminum flakes and a high pH silicate binder, but no resin binder. WO-2007/081831 discloses a composition for ceiling leaks in engines comprising organic and inorganic fibers and a high pH silicate binder. JP-201253798 discloses a polyimide resin with low water absorption for use in engine cooling water system components such as pipes and housings comprising a polyamide resin together with a fibrous reinforcing agent.

US Patent US-4524158 British Patent Specification GB-1218485 US-2003/0056691 WO-2007/081831 JP-201253798

The invention is presented in its various forms in the appended claims.

Specifically, the automotive engine cooling system leaktight formulation comprises a polymer resin and a particle package, the particle package comprising first, preferably natural fibers having a first fiber length and a greater amount of a second A second, preferably natural fiber having a fiber length is included.

The present invention provides an automotive engine cooling system leaktight formulation comprising a polymer resin and a particulate package, the particulate package comprising oilseed meal and wood flour.

The present invention provides an automotive engine cooling system leak tight formulation that can maintain repairs after draining and refilling coolant.

The present invention preferably provides an automotive engine cooling system leaktight formulation whose liquid component is miscible with a monoethylene glycol-water mixture.

The present invention preferably provides an automotive engine cooling system leaktight formulation whose solid components remain suspended in a monoethylene glycol-water mixture.

Polymer resin:
Polymeric resins for the present invention are selected to bond with coated or uncoated metal surfaces. The polymeric resin is preferably an acrylate, more preferably a methyl methacrylate-ethyl acrylate copolymer or a methyl methacrylate-butyl acrylate copolymer. Without wishing to be bound by theory, the presence of small pendant groups minimizes steric hindrance and the high charge allows a strong affinity to adhere to metals. The polymeric resin is most preferably a copolymer of methyl methacrylate and butyl acrylate. The copolymer may have an average molecular weight between 200,000 and 300,000 Daltons using the Mz standard. More preferably, the copolymer has an average molecular weight between 100,000 and 400,000 Daltons using the Mz standard. A suitable tool for determining the molecular weight of this material is found in Andrzej, R., Piotr, M., Aginieszka, K., "Determination of absolute molar mass distribution", Annals of Warsaw University of Life Sciences-SGGW, Forestry and Wood. Technology 2010, No.72, pp.206-2120.

Preferably, the copolymer is added to the formulation in a solvent such as toluene, which allows the polymer resin to be easily mixed with the other ingredients of the formulation.

In the present invention, the polymer resin preferably has a glass transition temperature between 30°C and 80°C, more preferably between 40°C and 60°C, most preferably between 45°C and 55°C.

The cooling system associated with the present invention operates at a nominal temperature of approximately 88°C. Thus, it is at and around this temperature, particularly in the temperature range of 80-100° C., that the compositions of the present invention are effective in performing sealing. However, the compositions of the present invention are further advantageous in that they remain suspended and do not precipitate solids at temperatures as low as 10°C. This is important because current cooling systems are normally held under pressure and it can be dangerous to open the system and add leak-proofing ingredients at operating temperatures. Clearly, a leaking cooling system may not be under pressure, and the degree of residual pressure is usually not evident. It is therefore a further object of the present invention to provide automotive engine cooling system leaktight formulations which are miscible with water-monoethylene glycol compositions within the temperature range of 10-100°C.

The combination of molecular weight and glass transition temperature serves to define the molar ratio of monomers in copolymers suitable for practicing the present invention.

Particle package:
The particle package of the present invention contains two or more types of fibers. These are referred to in the present invention as first and second fibers. The fibers are preferably organic fibres, more preferably natural fibres, most preferably cellulose or cellulose-based fibres. Organic fibers are preferably wood flour and oilseed meal fibers. The organic fibers are preferably of different average lengths (as determined by optical microscopy) to form a bimodal fiber length distribution. Other fiber types are synthetic organic fibers such as polyethylene terephthalate and nylon. Metal fibers are not preferred as they can cause galvanic corrosion. The fibers preferably have a glass transition temperature above normal engine operating temperature (here assumed to be 150° C.), so cellulose is preferred.

The wood flour is preferably softwood fibres. Such materials are produced by grinding and sieving softwoods such as spruce and pine to give fine particles in the formulation. Preferably, the wood flour has a moisture content of less than 15% and a particle size of 100 μm to 600 μm as determined by screening. In other words, less than 1% of the particles are retained by the 600 μm screen and at least 90% are retained by the 100 μm screen. Less than 40% of the fibers are retained by the 300 μm screen.

The first fiber length ranges from 50 μm to 500 μm and the second fiber length ranges from 1 to 25 μm. The first fiber is preferably wood flour as described above. The second fiber is preferably the oilseed meal fiber described above. This measurement is derived from measuring the profile of 200 fibers using an optical microscope.

The first fiber length preferably has a weight average first fiber length of 100 μm to 300 μm and a weight average second fiber length of 10 μm to 20 μm. This measurement was made by measuring the profile of 200 fibers using an optical microscope, assuming that the longest length defines the length of the cylinder and the width perpendicular to that length represents the diameter. , is derived by calculating the weight contribution to the average by assuming that the particles are represented as solid cylinders. This measurement method is preferred because the measurement of small fibers is problematic and this measurement method reduces their influence on the measurement.

The oilseed meal may be rapeseed meal or linseed meal, preferably pressed linseed meal, which is a by-product of linseed oil production in which the oil is pressed from the seed. Especially since oilseeds contain residual amounts of linoleic acid and alpha-linolenic fatty acid (approximately 2:1) from the oilseed pressing process, which provide some adhesive strength at engine operating temperatures, presumably by in situ polymerization. preferable. For this reason flaxseed meal is more preferred. The compositions of the present invention provide long-lasting leak repairs that do not dissolve away when new coolant is introduced. Weight values when referring to the second fiber relate to the sum of fiber and residual oil. Residual oil may range from 5-50% of the total weight, preferably 20-25% of that weight. The weight of fiber to oil can be determined by weighing, extracting with acetone, drying and weighing. The oil component, especially linseed oil, appears to have a functional effect, providing better sealing than without it. Specifically, the ability to withstand coolant refills is improved.

In the formulations of the invention, the weight ratio of shorter fibers to longer fibers is preferably between 1:2 and 1:12, preferably between 1:4 and 1:8, most preferably 1:5. .6.

In the formulations of the present invention, the particle packaged wood flour and oilseed meal are preferably between 1:2 and 1:12, preferably between 1:4 and 1:8, most preferably 1:5. .6 weight ratio.

Interaction of the polymer resin and the particle package (of the first and second fibers):
The present formulation of polymer resin, wood flour, and oilseed meal interact together to prevent leakage of coolants mixed with monoethylene glycol-water mixtures as determined using ASTM-D3147-06. was found to provide sealing with respect to This does not involve blockage of the cooling system. While not wishing to be bound by theory, it is believed that the sealing ability of particulate materials is related to how these materials behave at the site of a leak. Because of its size, the fine wood flour cannot agglomerate into large enough clumps to seal the slot. Instead, a piece (or pieces) of irregularly shaped oilseed meal is moved to the site of the leak. Additional clumping and cohesion is provided by the resin, and within a short period of time the oilseed meal pieces are held at the site of the leak before being extruded through it, allowing the wood flour and resin to remain between the oilseed meal. fill the space of This formulation is layered on top of itself to provide the final seal. The combination of selected resins and two types of fibrous materials with bimodal particle size distributions provides surprisingly good sealing in a short period of time. This may be due to polymerization of wood fiber and oilseed meal. Once the resin has cured, the materials bond to form a permanent seal after the coolant reaches the glass transition temperature of the resin.

The polymer resin:particle package weight ratio may be between 1:0.1 and 1:2, preferably between 1:0.5 and 1:1.5, optimally more preferably 1:1.05. found to be effective.

Additive:
Some embodiments of the present invention may include additives to maintain performance and antifoam products may be added to the formulation to limit foaming. In other embodiments, antimicrobial products can be added to inhibit microbial growth that can lead to blockages within the cooling system. In still other embodiments, buffering additives are included in the formulation to adjust the pH. A preferred buffering range is pH 6-9, more preferably pH 6.5-8.0, and a preferred buffering agent is trisodium citrate. The absence of silicate binders allows the composition to be buffered, which imparts a particularly high pH and is particularly corrosive and dangerous to use when mixed with hot coolants, especially to the skin or eyes. Dangerous in contact with The composition is therefore much safer.
Specific aspects of the present invention are as follows.
[Aspect 1]
An automotive engine cooling system leaktight formulation comprising a polymeric resin and a particulate package, said particulate package comprising first fibers having a first fiber length and a second fiber length having a greater amount of a second fiber length. 2 fibers.
[Aspect 2]
An automobile engine according to aspect 1, wherein the ratio of said first fibers to said second fibers is 1:2 to 1:12, and said second fibers are longer than said first fibers. Cooling system leak proof formulation.
[Aspect 3]
The automotive engine cooling system leaktight formulation of aspect 1 or aspect 2, wherein the first fiber length ranges from 50 μm to 500 μm and the second fiber length ranges from 1 to 25 μm.
[Aspect 4]
4. The automotive engine cooling system leaktight formulation according to aspect 3, wherein the weight average first fiber length is from 100 μm to 300 μm and the weight average second fiber length is from 10 μm to 20 μm.
[Aspect 5]
A motor vehicle engine according to aspect 1, wherein said first fibers are wood flour and have a particle size distribution such that at least 90% are retained by a 100 µm screen and less than 1% are retained by a 600 µm screen. Cooling system leak proof formulation.
[Aspect 6]
An automotive engine cooling system leaktight formulation according to any of aspects 1-5, wherein the natural fibers are oilseed meal and wood flour.
[Aspect 7]
7. The automotive engine cooling system leaktight formulation of aspect 6, wherein the oilseed meal is pressed linseed meal.
[Aspect 8]
The automotive engine cooling system leaktight formulation according to any of aspects 3-5, wherein the weight ratio of said first fibers to said second fibers is between 1:4 and 1:8.
[Aspect 9]
The automotive engine cooling system leaktight formulation of any of aspects 1-8, wherein said polymeric resin comprises a methyl methacrylate copolymer.
[Aspect 10]
10. The automotive engine cooling system leaktight formulation according to aspect 9, wherein said polymeric resin comprises one of methyl methacrylate-ethyl acrylate copolymer or methyl methacrylate-butyl acrylate copolymer.
[Aspect 11]
11. The automotive engine cooling system leaktight formulation of any of aspects 1-10, wherein said polymeric resin has a Mz average molecular weight of between 200,000 and 300,000 Daltons.
[Aspect 12]
The automotive engine cooling system leaktight formulation of any of aspects 1-11, wherein said polymeric resin has a glass transition temperature between 30°C and 80°C.
[Aspect 13]
A motor vehicle engine cooling system leak according to any of aspects 1-12, wherein the weight ratio of said polymeric resin to the sum of said first and second fibers is between 1:0.5 and 1:1.5. stopping compound.
[Aspect 14]
14. A method of repairing coolant leaks using the automotive engine cooling system leak tight formulation of any of aspects 1-13 by introducing said formulation into the automotive engine cooling system and operating the engine.
[Aspect 15]
15. The method of aspect 14, wherein the automotive engine cooling system comprises a monoethylene glycol-based coolant.

Leak stop formulation 15MN002 was blended according to the following recipe.

粒子パッケージに関して１：５．６の木粉：圧搾亜麻仁粕の比、及び１：１．０５のアクリル樹脂コポリマーと粒子パッケージとの比を用いて、漏れ止め配合物を水中にブレンドした。

The leak stop formulation was blended in water using a ratio of wood flour:pressed linseed meal of 1:5.6 for the particle package and a ratio of acrylic resin copolymer to particle package of 1:1.05.

The thermoplastic resins used in this embodiment were selected based on several different criteria such as block copolymer combinations, solubility parameters, available morphologies and solvent systems, glass transition temperatures, molecular weights, densities, and the like.

In these tests, formulation no. It gave a resin designated 884-000174-0612-NAR-EN-CDP. As the coolant container cooled, the resin returned to its glassy state and the seal became increasingly brittle, especially for low molecular weight polymers, but filling was regular enough to maintain the seal. Excessively brittle resins can break when pressure is applied to the container.

The following comparative formulations were also tested.

Ｔｇ＝１０９℃のポリアクリル酸は、規定した樹脂と同等の分子量及び同じ溶液濃度のものであった。本発明においては、ガラス転移温度は、ＡＳＴＭ－Ｅ１３５６－０８(２０１４)：示差走査熱量測定によってガラス転移温度を付与するための標準試験法を用いて求めることができる。

The polyacrylic acid with Tg=109° C. was of similar molecular weight and same solution concentration as the specified resin. In the present invention, the glass transition temperature can be determined using ASTM-E1356-08 (2014): Standard Test Method for Assigning Glass Transition Temperatures by Differential Scanning Calorimetry.

This formulation was then subjected to tests simulating conditions in an automotive coolant system.

Test method:
The developed formulation was evaluated along with a series of competing products using the Leak Stopping Additive Performance Test Method from the American National Standards Institute: ASTM-D3147-06.

The ASTM-D3147-06 method involves preparing a rectangular stainless steel 12-13.5 liter vessel designed to hold pressures up to 140 kPa. A heater and pump were installed to allow testing over a range of temperatures and pressures. A test plate constructed of solid brass could be attached to the reservoir using a gasket. The test plate can be provided with slits of various widths with a length of 12.7 mm. The test plate can provide 3 holes each of the same size, or 9 holes of various sizes. The test simulates the operating conditions of an automobile engine, such as operation at temperatures between 84° C. and 92° C. and pressures between 88 kPa and 118 kPa, to measure the leak through the holes after adding the leak stop product to the coolant. stipulated to

The encapsulation test used to evaluate the present invention was divided into 6 stages based on the ASTM-D3147-06 standard. A stainless steel vessel, circulation pump, and heater were provided and connected to the pressurization device. Spaces were provided along adjacent faces of the container into which replaceable brass plates with holes or slots could be inserted. For the final test, a plate with a 0.762 mm (0.030 inch) size hole and a 0.254 mm (0.010 inch) slot was selected. Plates with holes and slots of these dimensions were selected because these are the largest holes desired according to ASTM that must be sealed without the possibility of causing inconvenience to the automotive cooling system by the leak-tight product. . Some products were unable to pass the test at these dimensions, so they were also tested using the smaller hole size of 0.020 inch.

Step 1 included adding coolant and 214 mL of a leak stop formulation (50/50 monoethylene glycol and water by volume to 12 L of coolant) to a vessel and then heating to about 88°C. board. A pump was used to circulate the coolant and formulation mixture.

Step 2 involved pressurizing the test sample to 103±15 kPa (15±2 psi) while maintaining temperature and circulation for 2 hours.

Step 3 included cooling the sample without circulation while maintaining a test pressure of 103±15 kPa (15±2 psi) for 12-20 hours to simulate overnight conditions. board.

Step 4 involved releasing the pressure, then activating the circulation pump to reheat the sample and repressurize the vessel to 103±15 kPa (15±2 psi) when the temperature reached 88°C.

Step 5 included cooling the system to room temperature.

Step 6 included pressurizing the system again and running the system for an additional hour.

Sealing by recording fluid loss along with various other parameters such as fluid loss volume and ambient temperature and solution temperature as described by ASTM-D3147-06, and observations recorded in a general format. The stopping performance was evaluated. To "pass," the formulation must maintain a minimum working volume of 4.5 liters throughout the duration of the test.

In addition, harmlessness testing was performed including two forms used in ASTM standards. The first form is the sieve test, in which the sample coolant and formulated mixture are sieved through an 850 μm sieve both before and after the test to remove gummed particles, gels, that can clog engine components such as radiator tubes. Particles or visible signs of particles were considered a failure.

The second configuration is the blockage test, performed by replacing the plate used in the performance test with a larger one representing the dimensions of the coolant passage or radiator. These slots were 0.635 mm wide and 12.7 mm long. To pass this test, there must be no seals formed over the slits or holes, allowing coolant to drain freely from the system. As such, it represents a formulation that does not clog any flow paths in the cooling system.

Test results:
The present invention performed to a higher level than any of the current products on the market. This new formulation exhibited a 100% pass rate for the ASTM-D3147-06 sealing test and maintained effective sealing after three subsequent drain and refill operations.

The table below compares the results of the test formulation 15MN002 and several products available on the market at the time of testing.

表１は、既存の販売品はいずれも、０．７６２ｍｍ（０．０３０インチ）の寸法の孔、及び０．２５４ｍｍ（０．０１０インチ）のスロットを有するプレートを用いたＡＳＴＭ－Ｄ３１４７－０６試験を信頼性を持って合格することができなかったことを示す。更に、このデータは、好ましいポリマータイプと組み合わせて用いた２種類の天然繊維の組み合わせは、個々に用いた場合の繊維よりも良好であったことを示す。

Table 1 shows that all existing commercial products tested ASTM-D3147-06 using plates with 0.762 mm (0.030 inch) size holes and 0.254 mm (0.010 inch) slots. could not be passed reliably. Furthermore, the data show that the combination of the two natural fibers used in combination with the preferred polymer types performed better than the fibers when used individually.

Formulation 15MN002 consistently passed this test. This formulation also passed the same test after refilling the test vessel four times with new coolant, indicating that it exceeded the requirements for permanent repairs specified in this standard.

This formulation also passed critical non-hazard testing designed to ensure that small boreholes in cooling systems remain unobstructed when using cooling system leak tightness products. In this test, the formulation must allow free drainage of coolant. The new formulation was given a "pass" on good morphology with laminar flow.

Competitive products failed to reliably pass the ASTM-D3147-06 sealing test.

The present invention provides an improved leak tightness product for sealing holes in engine cooling systems.

The present invention can be applied in practice in the form of a novel product that acts as an excellent engine cooling system leak repair agent.

The test results show that this new formulation is superior in all respects tested. Additionally, the seal can be considered permanent under the terms herein. Permanent is taken in the present application to mean that the sealing effect persists even after three changes of coolant in the system after repair.

Claims (12)

An automotive engine cooling system leaktight formulation comprising a polymeric resin and a particulate package, said particulate package comprising first fibers having a first fiber length and a second fiber length having a greater amount of a second fiber length. 2 fibers , said polymer resin comprising a methyl methacrylate copolymer, said polymer resin having a Mz average molecular weight of between 200,000 and 300,000 Daltons and a glass transition temperature of between 30°C and 80°C. Cooling system leak proof formulation. 2. The method according to claim 1, wherein the weight ratio of said first fibers to said second fibers is 1:2 to 1:12, and said second fibers are longer than said first fibers. Automotive engine cooling system leak tight formulation. The automotive engine cooling system leaktight formulation of claim 1 , wherein said first fiber length ranges from 50 µm to 500 µm and said second fiber length ranges from 1 to 25 µm. 4. The automotive engine cooling system leaktight formulation of claim 3, wherein the weight average first fiber length is between 100 μm and 300 μm and the weight average second fiber length is between 10 μm and 20 μm. 2. A vehicle according to claim 1, wherein said first fibers are wood flour and have a particle size distribution such that at least 90% are retained by a 100 [mu]m screen and less than 1% are retained by a 600 [mu]m screen. Engine cooling system leak-proof formulation. An automotive engine cooling system leaktight formulation according to any preceding claim , wherein said first fibers and said second fibers are natural fibers, said natural fibers being oilseed meal and wood flour. . 7. The automotive engine cooling system leaktight formulation of claim 6, wherein said oilseed meal is pressed linseed meal. An automotive engine cooling system leaktight formulation according to any of claims 3-5, wherein the weight ratio of said first fibers to said second fibers is between 1:4 and 1:8. 2. The automotive engine cooling system leaktight formulation of claim 1 , wherein said polymeric resin comprises one of methyl methacrylate-ethyl acrylate copolymer or methyl methacrylate-butyl acrylate copolymer. A motor vehicle engine cooling system according to any preceding claim, wherein the weight ratio of said polymer resin to the sum of said first and second fibers is between 1:0.5 and 1: 1.5 . leak-proof compound. A method of repairing coolant leaks by using the automotive engine cooling system leak tight formulation of any of claims 1-10 , introducing said formulation into the automotive engine cooling system and operating the engine. 12. The method of claim 11 , wherein the automotive engine cooling system comprises a monoethylene glycol-based coolant.